Premade NiMH packs at more reasonable prices?

knightmb

100 kW
Joined
May 7, 2006
Messages
1,071
Location
Franklin, TN
Since the NiMH packs seem to have gone up in price, any tried these battery packs as they appear to be at the "traditional" prices I'd seen before.

http://www.poweridestore.com/NiMH-Battery-Packs
 
Expensive?
Where would one get better/cheaper NiMH?
 
http://www.sanforce.com.hk/en/

I see the word sanforce printed on the green pack.


This is kinda funny ( dependin on your version of " funny "
.
http://www.sanforce.com.hk/en/Product/ProductDetail.aspx?ProductID=9

Qutoe "You can even use 72V by using 2 packs of 36V battery, which can blow your bike into air"
 
Ypedal said:
Qutoe "You can even use 72V by using 2 packs of 36V battery, which can blow your bike into air"

sounds pretty cool to me 8) I notice in the pics their batteries seem to be suspened in mid air in a forest. :lol:


I heard of 1 person who ordered direct from them in china and seemed happy. The 20AH prismatics looks nice too.
 
Whilst these prices seem good you have to be carefull.

I have tested NIMH from 8 or so manufacturers, measuring capacity at discharge rates as high as 10C with varying charge rates. Of these some cells would not deliver rated capacity at anything over a .2C discharge rate. The very worst cells delivered less than 60% at anything over 1C. For these very poor cells I sourced another sample and retested - with no difference in performance.

The very best cells would deliver 95+% back at 10C - best of all they would also happily charge to 98+% at rates as high as 1C.

So, given most people do not want/need a 40 mile range or the accompanying 12+KG of battery it seems to me cell choice is very important.

One of my bikes for eg has a battery which weighs 4.8KG - is a 48V 7.4AH pack. It is truly happy delivering 50+ amps and still returning 95+% of charge at that rate - meaning even though it is small in capacity when I peg the throttle it really delivers the amps yet when cruising at 23-24mph it gives excellent range.

By comparison - a battery like others I have tested would really suffer when pushed hard - delivering less than 4AH.

Obviously - this only applies if the motor/controller combo is likely to ever draw over .2C from your pack - which on mine is about 1.48A ~ 71W - hardly likely! OK - a bit OTT that - but even at the 1C rate a lot of cells were terrible - on 7.4AH 48V that 1C is 355W. Clearly a lot of motors draw more than this - pretty much all that exceed 20mph in fact!

So, tbh I really don't trust any figures from battery resellers unless proper tests have been conducted. I have cells here which were claimed to do 10C and be 3500mah - yet in fact they never EVER delivered more than 2200mah!

FWIW the cells I use - for the 48V 7.4AH pack cost me £180 - about $360. I could have spent £90 $180 for the same rated capacity - fortunately I tested them first!

Scott
 
Scott, ever test the batteryspace.com NiMH packs? For example, http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2538
 
Liberator said:
Scott, ever test the batteryspace.com NiMH packs? For example, http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2538

Nope - don't think it would be worthwhile though.

quoted from the site -

Standard discharging rate: 13Amp ( Recommended and warrantied)
Highest Discharging rate for continuous running: 40Amp ( high discharging rate will recue battery capacity )
Max. Discharging capability for short time: 60Amp ( Not recommend as working rate )

all tells me - without reading between the lines - these cells deliver less than 13AH at anything over 1C

Also tells me (as expected - due to the cell shape(heating)) anything over 5C is a no-no

The fact they are less than happy at >1C tells me the cells are simply not as good as some others.

Granted - they do give a lot of capacity and in a 48V 40cell pack as long as you are drawing <600W they will shine.

Obviously, for every second you ask for more than 600W you are throwing capacity away - for this reason they would not find there way onto any bike I run!

Scott
 
Cool. Thanks so much for the info. I'm certainly gonna be drawing some decent wattage as my commute to work has some hills, is over 8 miles round trip, and I'm 6'1" and 220lbs so I'm getting up there with the power. I guess we'll see once I install my Watt's Up meter this weekend but I may just decide to run these SLA's until they die.

It sure sounds like anything outside of SLA's I'd want would cost me another $1000!
 
Ypedal said:
I just want to know what cells your 7.4ah pack is made of ? please ?

exact cells......

http://cgi.ebay.co.uk/Sub-C-3700mAh-high-capacity-NiMH-With-TAB_W0QQitemZ320113901399QQihZ011QQcategoryZ1200QQrdZ1QQcmdZViewItem

the description is muddled. they also sell 4300's now - equally as good. I am using 80 of these 3700 items.

Last year I couldn't recommend these since I didn't really have enough cycles on them. They have long since passed any reasonable benchmark - well in excess of 600 (I stopped recording at 500) and still delivered 90+% on the bench test (at 500 cycles).

I was loathe to dissasemble the pack to extract a cell - hence no data between new and 500!

I've also been playing with some of my lipo. I have gathered together all my PQ2500 cells, stripped em from the packs and tested them individually. I had 13 good ones so wired 12 in series - was comical - bike doing 25mph with a 700g battery pack - not for long obviously!

Scott
 
That's great to hear you excellent results with those NiMH cells. You should start your own '600 cycle' club. :lol:
I'm almost at 70 cycles on my 2D cells, and I'd be really happy if they hold 90% at 500+ cycles.
 
I wish I bought those NiMh batteries a while ago because the Tenergy "D" cells could be had for as little as $5. Now those exact same batteries are up to $6.75. That's a $140 difference for my 80 cell project.

Hmmm... :?
 
So, modifying the original question of this thread, any decent pre-made NiMH packs out there that people HAVE tested and have experience with and ARE worth the price? While I'm a pretty handy guy, I don't trust myself with a soldering iron.
 
i have the sanforce ni-cads, 48 volts. the past month has been no problem, under hard riding, throttle fully opened, i get about 30km a charge.with the crystalight 406 btw, i paid an extra 300 cad, for the upgrade.
 
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